Biocidal combinations containing 4,5-dichloro-2-cyclohexyl-3-isothiazolone and certain commercial biocides

ABSTRACT

Synergistic microbicidal compositions are disclosed, comprising 4,5-dichloro-2-cyclohexyl-3-isothiazolone and one or more known microbicides for more effective, and broader control of microorganisms in various systems.

This is a divisional of application Ser. No. 07/844,254, filed Mar. 2,1992, now U.S. Pat. No. 5,185,355, which is a divisional of applicationSer. No. 07/625,281, filed Dec. 10, 1990, now U.S. Pat. No. 5,157,045.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention concerns microbicidal compositions which include anisothiazolone and one or more other biocides, and which are intended toprovide more effective and broader control of microorganisms in variousindustrial systems and for household products, agricultural products,and biomedical products, etc. In particular, the present inventionrelates to the use of a composition of4,5-dichloro-2-cyclohexyl-3-isothiazolone, with one or more of thefollowing [14] compounds: 3-iodo-2-propynylbutylcarbamate,1,2-dibromo-2,4-dicyanobutane, methylene-bis-thiocyanate, a mixture of4,4-dimethyloxazoline and 4,4-dimethyl-N-methyloxazoline,5-polyhydroxymethyleneoxy-methyl-1-aza-3,7-dioxabicyclo(3.3.0) octane,tetrachoroisophthalonitrile, 2-n-octyl-3-isothiazolone,5-bromo-5-nitro-1,3-dioxane, 2-bromo-2-nitropropanediol,hexahydro-1,3,5-triethyl-s-triazine, 2,2-dibromo-3-nitrilopropionamide,benzylbromoacetate, p-chloro-m-xylenol, and1,3,5-tris-(2-ethoxyl)-s-triazine.

The term "microbicidal" (or "antimicrobial" or "biocidal") as usedherein is intended to encompass, but is not restricted to, allbactericidal, fungicidal and algicidal activity.

2. Prior Art

Isothiazolones are described in U.S. Pat. Nos. 3,761,488; 4,105,431;4,252,694; 4,265,899 and 4,279,762, and elsewhere. Their use asmicrobicides is well known. The "second" components are commericalbiocides.

It is the principal object of this invention to provide synergisticcompositions which overcome disadvantages of known microbicidalcompositions.

SUMMARY OF THE INVENTION

We have found that compositions formed from4,5-dichloro-2-cyclohexyl-3-isothiazolone and one or more of thefollowing compounds: 3-iodo-2-propynylbutylcarbamate,1,2-dibromo-2,4-dicyanobutane, methylene-bis-thiocyanate, a mixture of4,4-dimethyloxazoline and 4,4-dimethyl-N-methyloxazoline,5-polyhydroxymethyleneoxy-methyl-1-aza-3,7-dioxabicyclo(3.3.0)octane,tetrachloroisophthalonitrile, 2-n-octyl-3-isothiazolone,5-bromo-5-nitro-1,3-dioxane, 2-bromo-2-nitropropanediol,hexahydro-1,3,5-triethyl-s-triazine, 2,2-dibromo-3-nitrilopropionamide,benzylbromoacetate, p-chloro-m-xylenol, and1,3,5-tris-(2-ethoxyl)-s-triazine unexpectedly afford synergisticantimicrobial activity against a wide range of microorganisms: thedisruptive action on the organisms by the two or more compounds togetheris unexpectedly greater than the sum of both compounds taken alone. Thissynergy does not arise from the expected activity of the components norfrom the expected improvement in activity. As a result of the synergy,the effective dose required can be lowered, which is not only moreeconomical but also increases safety margins. The synergisticcompositions of the present invention provide more effective and broadercontrol of microorganisms in a number of systems.

The present invention thus provides a composition having microbicidalactivity which includes 4,5-dichloro-2-cyclohexyl-3-isothiazolone and asecond component selected from one or more of the group consisting of:3-iodo-2-propynylbutylcarbamate, 1,2-dibromo-2,4-dicyanobutane,methylene-bis-thiocyanate, a mixture of 4,4-dimethyloxazoline and4,4-dimethyl-N-methyloxazoline,5-polyhydroxymethyleneoxy-methyl-1-aza-3,7-dioxabicyclo(3.3.0)octane,tetrachloroisophthalonitrile, 2-n-octyl-3-isothiazolone,5-bromo-5-nitro-1,3-dioxane, 2-bromo-2-nitropropanediol,hexahydro-1,3,5-triethyl-s-triazine, 2,2-dibromo-3-nitrilopropionamide,benzylbromoacetate; p-chloro-m-xylenol; and1,3,5-tris-(2-ethoxyl)-s-triazine wherein the weight ratio of4,5-dichloro-2-cyclohexyl-3-isothiazolone to the second component isfrom about 8:1 to about 1:4000.

Important applications of the synergistic antimicrobial compositions ofthe present invention include but are not limited to: inhibiting thegrowth of bacteria and fungi in aqueous paints and coatings, adhesives,sealants, latex emulsions, and joint cements; preserving wood;preserving cutting fluids, controlling slime-producing bacteria andfungi in pulp and papermills and cooling towers; as a spray or diptreatment for textiles and leather to prevent mold growth; protectingpaint films, especially exterior paints, from attach by fungi whichoccurs during weathering of the paint film; protecting processingequipment from slime deposits during manufacture of cane and beet sugar;preventing microorganism buildup and deposits in air washer or scrubbersystems and in industrial fresh water supply systems; preserving fuel;controlling microorganisms contamination and deposits in oil fielddrilling fluids and muds, and in secondary petroleum recovery processes;preventing bacterial and fungal growth in paper coatings and coatingprocesses; controlling bacterial and fungal growth and deposits duringthe manufacture of various specialty boards, e.g., cardboard andparticle board; preventing sap stain discoloration on freshly cut woodof various kinds; controlling bacterial and fungal growth in clay andpigment slurries of various types; as a hard surface disinfectant toprevent growth of bacteria and fungi on walls, floors, etc.; as apreservative for cosmetic and toiletry raw materials, floor polishes,fabric softeners, household and industrial cleaners; in swimming poolsto prevent algae growth; inhibiting the growth of harmful bacteria,yeasts, fungi on plants, trees, fruits, seeds, or soil; preservingagricultural formulations, electrodeposition systems, diagnostic andreagent products, medical devices; protecting animal dip compositionsagainst the buildup of microorganisms, and in photoprocessing to preventbuildup of microorganisms, and the like.

The compositions of the invention may be added separately to any systemor may be formulated as a simple mixture comprising its essentialingredients, and if desired a suitable carrier or solvent, or as anaqueous emulsion or dispersion.

The invention also provides a method of inhibiting the growth ofbacteria, fungi or algae in a locus subject to contamination bybacteria, fungi or algae, which comprises incorporating into or onto thelocus in an amount which is effective to adversely affect the growth ofbacteria, fungi or algae any of the compositions defined above.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT

The composition of the invention can be formulated as a solution in awide range of organic solvents. The solutions generally contain about 1to 30% by weight of the active composition. It is generally moreconvenient to provide the compositions in a water-diluted form: this maybe accomplished by adding an emulsifier to the organic solution followedby dilution with water.

In general, the weight ratio of4,5-dichloro-2-cyclohexyl-3-isothiazolone to second component in thecomposition may be in the range of from about 8:1 to about 1:4000. Theother specific and preferred ratios are given in the examples.

The synergism of two-component compositions is demonstrated by testing awide range of concentrations and ratios of compounds, generated bytwo-fold serial dilutions in a Trypticase Soy Broth (Difco) growthmedium of a microbicide in one dimension and another microbicide in thesecond dimension, against a bacterium Escherichia coli (ATCC 11229), orfungi Candida albicans (ATCC 11651), Aspergillus niger (ATCC 6275), orAureobasidium pullulans (ATCC 9348). Each test tube was inoculated tomake about 1-5×10⁷ bacteria per ml or 1-5×10⁵ fungi per ml. The lowestconcentrations of each compound or mixtures to inhibit visible growth(turbidity) at 37° for E. coli and at 30° C. for the fungi for 7 dayswere taken as the minimum inhibitory concentration (MIC). The MIC weretaken as end points of activity. End points for the mixtures of compoundA (4,5-dichloro-2-cyclohexyl-3-isothiazolone) and compound B (secondcomponent microbicide) were then compared with the end points for theisothiazolone A alone and compound B alone. Synergism was determined bya commonly used and accepted method described by Kull, F. C.; Eisman, P.C.; Sylwestrowicz, H. D. and Mayer, R. L., in applied Microbiology9:538-541 (1961) using the ratio determined by

    Qa/QA+Qb/QB=Synergy Index (SI)

wherein

QA=concentration of compound A in parts per million (ppm), acting alone,which produced an end point.

Qa=concentration of compound A in ppm, in the mixture, which produced anend point.

QB=concentration of compound B in ppm, acting alone, which produced anend point.

Qb=concentration of compound B in ppm, in the mixture, which produced anend point

when the sum of Qa/QA and Qb/QB is greater than one, antagonism isindicated. When the sum is equal to one additivity is indicated, andwhen less than one synergism is demonstrated.

The test results for demonstration of synergism of microbicidecombinations are shown in Tables 1 to 14. Each table concerns thecombination of 4,5-dichloro-2-cyclohexyl-3-isothiazolone and one othermicrobicide, and shows:

1. the identity of the second microbicide (compound B)

2. test against E. coli, C. albicans (C.alb), A. niger or A. pullulans(A. pullul)

3. the end-point activity in ppm measured by MIC for either compoundalone or their combinations

4. the synergy index (SI) based on the formula SI=Qa/QA+Qb/QB

5. the range of weight ratios for synergism; it will be appreciated bythose skilled in the art that the ratios given are approximate only.

                  TABLE 1                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 4,4-dimethyoxazoline + 4,4-dimethyl-N-                           methyloxazoline mixture                                                               end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             1         0                                                                   0.5       500        0.75   1:1000                                            0.25      1000       0.75   1:4000                                            0         2000                                                      E. coli   16        0                                                                   8         250        0.75   1:31                                              4         500        0.75   1:125                                             0         1000                                                      ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 5-bromo-5-nitro-1,5-dioxane                                              end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             4         0                                                                   2         6.2        0.56   1:3                                               2         12.5       0.62   1:6                                               1         12.5       0.37   1:12                                              1         25         0.50   1:25                                              0.5       25         0.37   1:50                                              0.5       50         0.62   1:100                                             0.25      50         0.56   1:200                                             0         100                                                       E. coli   16        0                                                                   8         25         0.75   1:3                                               4         50         0.75   1:12                                              2         50         0.62   1:25                                              1         50         0.56   1:50                                              0         100                                                       ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 2,2-dibromo-3-nitrilopropionamide                                        end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             4         0                                                                   2         31         0.52   1:16                                              1         31         0.27   1:31                                              1         62         0.31   1:62                                              1         125        0.37   1:125                                             0.5       125        0.25   1:250                                             0.5       250        0.37   1:500                                             0.25      250        0.31   1:1000                                            0.25      500        0.56   1:2000                                            0.12      500        0.53   1:4000                                            0         1000                                                      E. coli   16        0                                                                   4         31         0.75   1:8                                               0         62                                                        ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 1,3,5-tris-(2-ethoxyl)-s-triazine                                        end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             0.5       0                                                                   0.25      500        0.75   1:2000                                            0         2000                                                      E. coli   16        0                                                                   8         250        0.75   1:31                                              4         500        0.75   1:125                                             0         1000                                                      ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = methylene-bis-thiocyanate                                                end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        A. pullulans                                                                            8         0                                                                   4         16         0.75   1:4                                               2         32         0.75   1:16                                              1         32         0.62   1:32                                              0.5       32         0.56   1:64                                              0.25      32         0.53   1:125                                             0         64                                                        C. albicans                                                                             1         0                                                                   0.5       4          0.63   1:8                                               0.5       8          0.75   1:16                                              0         32                                                        E. coli   62        0                                                                   32        32         0.75   1:1                                               16        32         0.50   1:2                                               16        62         0.75   1:4                                               8         62         0.62   1:8                                               4         62         0.56   1:16                                              2         62         0.53   1:31                                              0         125                                                       ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = benzylbromoacetate                                                       end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             1         0                                                                   0.5       0.5        0.51   1:1                                               0.5       1          0.53   1:2                                               0.5       2          0.56   1:4                                               0.5       4          0.62   1:8                                               0.5       8          0.75   1:16                                              0.25      16         0.75   1:64                                              0         32                                                        E. coli   16        0                                                                   8         31         0.62   1:4                                               8         62         0.75   1:8                                               4         125        0.75   1:32                                              0         250                                                       ______________________________________                                    

                  TABLE 7                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = tetrachloroisophthalonitrile                                             end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        A. pullulans                                                                            8         0                                                                   4         1          0.56   4:1                                               4         2          0.63   2:1                                               4         4          0.75   1:1                                               2         4          0.50   1:2                                               1         4          0.37   1:4                                               1         8          0.62   1:8                                               0.5       8          0.56   1:16                                              0         16                                                        E. niger  8         0                                                                   4         2          0.63   2:1                                               4         4          0.75   1:1                                               2         4          0.50   1:2                                               2         8          0.75   1:4                                               0         16                                                        ______________________________________                                    

                  TABLE 8                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 5-polyhydroxymethyleneoxy-methyl-l-aza-3,7-                      dioxabicyclo(3.3.0)octane                                                             end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             4         0                                                                   2         500        0.75   1:250                                             1         1000       0.75   1:1000                                            0         2000                                                      E. coli   16        0                                                                   8         125        0.75   1:16                                              4         250        0.75   1:62                                              0         500                                                       ______________________________________                                    

                  TABLE 9                                                         ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = p-chloro-m-xylenol                                                       end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             2         0                                                                   1         8          0.62   1:8                                               1         16         0.75   1:16                                              0.5       31         0.75   1:62                                              0.25      31         0.62   1:125                                             0         62                                                        E. coli   16        0                                                                   8         125        1.00   1:16                                              0         250                                                       ______________________________________                                    

                  TABLE 10                                                        ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 2-n-octyl-3-isothiazolone                                                end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             0.5       0                                                                   0.25      0.12       0.75   2:1                                               0         0.5                                                       A. pullulans                                                                            8         0                                                                   4         1          0.75   4:1                                               2         1          0.50   2:1                                               2         2          0.75   1:1                                               0         4                                                         E. coli   16        0                                                                   4         125        0.75   1:31                                              0         250                                                       ______________________________________                                    

                  TABLE 11                                                        ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 3-iodo-2-propynylbutylcarbamate                                          end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             1         0                                                                   0.5       0.5        0.56   1:1                                               0.5       1          0.62   1:2                                               0.5       2          0.75   1:4                                               0.25      4          0.75   1:16                                              0.12      4          0.62   1:32                                              0         8                                                         A. pullulans                                                                            8         0                                                                   4         0.5        0.62   8:1                                               4         1          0.75   4:1                                               2         1          0.50   2:1                                               2         2          0.75   1:1                                               0         4                                                         A. niger  8         0                                                                   4         2          0.75   2:1                                               2         4          0.75   1:2                                               1         4          0.62   1:4                                               0         8                                                         E. coli   16        0                                                                   4         125        0.75   1:31                                              2         125        0.62   1:62                                              0         250                                                       ______________________________________                                    

                  TABLE 12                                                        ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 1,2-dibromo-2,4-dicyanobutane                                            end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             1         0                                                                   0.5       4          0.62   1:8                                               0.5       8          0.75   1:16                                              0.25      16         0.75   1:62                                              0         32                                                        A. pullulans                                                                            8         0                                                                   4         16         0.75   1:4                                               2         32         0.75   1:16                                              0         64                                                        E. coli   16        0                                                                   8         16         0.75   1:2                                               0         62                                                        ______________________________________                                    

                  TABLE 13                                                        ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = hexahydro-1,3,5-triethyl-s-triazine                                      end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             0.5       0                                                                   0.25      250        0.62   1:1000                                            0.25      500        0.75   1:2000                                            0         2000                                                      E. coli   16        0                                                                   8         125        0.75   1:16                                              4         250        0.75   1:62                                              0         500                                                       ______________________________________                                    

                  TABLE 14                                                        ______________________________________                                        Compound A = 4,5-dichloro-2-cyclohexyl-3-isothiazolone                        Compound B = 2-bromo-2-nitropropanediol                                               end-point activity in ppm                                                       Compound  Compound   Synergy                                                                              Ratio                                   ORGANISM  A         B          Index  (A:B)                                   ______________________________________                                        C. albicans                                                                             4         0                                                                   2         12.5       0.56   1:6                                               2         25         0.62   1:12                                              1         25         0.37   1:25                                              0.5       25         0.25   1:50                                              0.5       50         0.37   1:100                                             0.25      50         0.31   1:200                                             0.25      100        0.56   1:400                                             0         200                                                       E. coli   62        0                                                                   16        50         0.75   1:3                                               8         50         0.62   1:6                                               4         50         0.56   1:12                                              2         50         0.53   1:25                                              1         50         0.52   1:50                                              0         100                                                       ______________________________________                                    

As can be seen by review of Table 1-14, the compositions of theinvention demonstrate synergistic microbicidal activity as measured byminimum inhibitory concentrations (MIC) and show surprisingly greateractivity than the algebraic sum of the individual components which makeup each composition.

The synergistic activities of the compositions of the invention in mostcases are applicable to bacteria, fungi, and a mixture of bacteria andfungi. Thus, the combinations not only lower the use-level of biocidebut also broaden the spectrum of activity. This is especially useful insituations where either component alone does not achieve the bestresults due to weak activity against certain organisms.

What is claimed is:
 1. A microbicidal composition comprising asynergistic mixture, the first component of which is4,5-dichloro-2-cyclohexyl-3-isothiazolone and the second component ofwhich is selected from the group consisting of5-bromo-5-nitro-1,3-dioxane, 2-bromo-2-nitropropanediol, andhexahydro-1,3,5-triethyl-s-triazine, wherein the synergistic weightratio of first component to second component is in the range of fromabout 8:1 to about 1:4000.
 2. The composition of claim 1, wherein theratio of the first component to the second component,5-bromo-4-nitro-1,3-dioxane, is in the range of from about 1:3 to about1:200.
 3. The composition of claim 1, wherein the ratio of the firstcomponent to the second component, hexahydro-1,3,5-triethyl-s-triazine,is in the range of from about 1:16 to about 1:2000.
 4. The compositionof claim 1, wherein the ratio of the first component to the secondcomponent, 2-bromo-2-nitropropanediol, is in the range of from about 1:3to about 1:400.
 5. A composition useful for inhibiting the growth ofmicroorganisms selected from the group consisting of bacteria, fungi andmixture thereof in a locus comprising about 1 to about 30% of thecomposition of claim 1 and a carrier.
 6. The composition according toclaim 5, wherein the carrier further comprises an emulsifier and water.7. A method for inhibiting the growth of a member selected from thegroup consisting of bacteria, fungi, algae and mixtures thereof in alocus subject to contamination by said member, which comprisesincorporating onto or into the locus, in an amount which is effective toadversely affect the growth of said member, the composition of claim 1.8. The method of claim 7 wherein the locus is an aqueous medium, and thecomposition additionally contains an emulsifier and water.